fix 修正离线设备判断逻辑

Src/Dlhis.Basic/Device/Services/Implements/DeviceService.cs

@@ -298,16 +298,24 @@ public class DeviceService : IDeviceService
         var list = new List<DeviceEntity>();
         foreach (var device in devices)
         {
-            var regis = deviceRegistrys.FirstOrDefault(x => x.DeviceUniqueNo == device.UniqueNo);
-            if (regis == null)
+            if(device.HeartbeatInterval > 0)
             {
-                continue;
+                var regis = deviceRegistrys.FirstOrDefault(x => x.DeviceUniqueNo == device.UniqueNo);
+                if (regis == null)
+                {
+                    continue;
+                }
+                TimeSpan timeDifference = DateTime.Now - regis.LastHeartbeatTime;
+                if (timeDifference.TotalSeconds > (device.HeartbeatInterval * 3))
+                {
+                    list.Add(device);
+                }
             }
-            TimeSpan timeDifference = DateTime.Now - regis.LastHeartbeatTime;
-            if (timeDifference.TotalSeconds > (device.HeartbeatInterval * 3))
+            else
             {
                 list.Add(device);
             }
+            
         }
         return list;
     }